/* ***************************************************************************
 *
 * ftglyph.h
 *
 * FreeType convenience functions to handle glyphs (specification).
 *
 * Copyright (C) 1996-2021 by
 * David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */


/* *************************************************************************
 *
 * This file contains the definition of several convenience functions that
 * can be used by client applications to easily retrieve glyph bitmaps and
 * outlines from a given face.
 *
 * These functions should be optional if you are writing a font server or
 * text layout engine on top of FreeType.  However, they are pretty handy
 * for many other simple uses of the library.
 *
 */


#ifndef FTGLYPH_H_
#define FTGLYPH_H_


#include <freetype/freetype.h>

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif


FT_BEGIN_HEADER


/* *************************************************************************
 *
 * @section:
 * glyph_management
 *
 * @title:
 * Glyph Management
 *
 * @abstract:
 * Generic interface to manage individual glyph data.
 *
 * @description:
 * This section contains definitions used to manage glyph data through
 * generic @FT_Glyph objects.  Each of them can contain a bitmap,
 * a vector outline, or even images in other formats.  These objects are
 * detached from @FT_Face, contrary to @FT_GlyphSlot.
 *
 */


/* forward declaration to a private type */
typedef struct FT_Glyph_Class_ FT_Glyph_Class;


/* *************************************************************************
 *
 * @type:
 * FT_Glyph
 *
 * @description:
 * Handle to an object used to model generic glyph images.  It is a
 * pointer to the @FT_GlyphRec structure and can contain a glyph bitmap
 * or pointer.
 *
 * @note:
 * Glyph objects are not owned by the library.  You must thus release
 * them manually (through @FT_Done_Glyph) _before_ calling
 * @FT_Done_FreeType.
 */
typedef struct FT_GlyphRec_ *FT_Glyph;


/* *************************************************************************
 *
 * @struct:
 * FT_GlyphRec
 *
 * @description:
 * The root glyph structure contains a given glyph image plus its advance
 * width in 16.16 fixed-point format.
 *
 * @fields:
 * library ::
 * A handle to the FreeType library object.
 *
 * clazz ::
 * A pointer to the glyph's class.  Private.
 *
 * format ::
 * The format of the glyph's image.
 *
 * advance ::
 * A 16.16 vector that gives the glyph's advance width.
 */
typedef struct FT_GlyphRec_ {
    FT_Library library;
    const FT_Glyph_Class *clazz;
    FT_Glyph_Format format;
    FT_Vector advance;
} FT_GlyphRec;


/* *************************************************************************
 *
 * @type:
 * FT_BitmapGlyph
 *
 * @description:
 * A handle to an object used to model a bitmap glyph image.  This is a
 * sub-class of @FT_Glyph, and a pointer to @FT_BitmapGlyphRec.
 */
typedef struct FT_BitmapGlyphRec_ *FT_BitmapGlyph;


/* *************************************************************************
 *
 * @struct:
 * FT_BitmapGlyphRec
 *
 * @description:
 * A structure used for bitmap glyph images.  This really is a
 * 'sub-class' of @FT_GlyphRec.
 *
 * @fields:
 * root ::
 * The root @FT_Glyph fields.
 *
 * left ::
 * The left-side bearing, i.e., the horizontal distance from the
 * current pen position to the left border of the glyph bitmap.
 *
 * top ::
 * The top-side bearing, i.e., the vertical distance from the current
 * pen position to the top border of the glyph bitmap.  This distance
 * is positive for upwards~y!
 *
 * bitmap ::
 * A descriptor for the bitmap.
 *
 * @note:
 * You can typecast an @FT_Glyph to @FT_BitmapGlyph if you have
 * `glyph->format == FT_GLYPH_FORMAT_BITMAP`.  This lets you access the
 * bitmap's contents easily.
 *
 * The corresponding pixel buffer is always owned by @FT_BitmapGlyph and
 * is thus created and destroyed with it.
 */
typedef struct FT_BitmapGlyphRec_ {
    FT_GlyphRec root;
    FT_Int left;
    FT_Int top;
    FT_Bitmap bitmap;
} FT_BitmapGlyphRec;


/* *************************************************************************
 *
 * @type:
 * FT_OutlineGlyph
 *
 * @description:
 * A handle to an object used to model an outline glyph image.  This is a
 * sub-class of @FT_Glyph, and a pointer to @FT_OutlineGlyphRec.
 */
typedef struct FT_OutlineGlyphRec_ *FT_OutlineGlyph;


/* *************************************************************************
 *
 * @struct:
 * FT_OutlineGlyphRec
 *
 * @description:
 * A structure used for outline (vectorial) glyph images.  This really is
 * a 'sub-class' of @FT_GlyphRec.
 *
 * @fields:
 * root ::
 * The root @FT_Glyph fields.
 *
 * outline ::
 * A descriptor for the outline.
 *
 * @note:
 * You can typecast an @FT_Glyph to @FT_OutlineGlyph if you have
 * `glyph->format == FT_GLYPH_FORMAT_OUTLINE`.  This lets you access the
 * outline's content easily.
 *
 * As the outline is extracted from a glyph slot, its coordinates are
 * expressed normally in 26.6 pixels, unless the flag @FT_LOAD_NO_SCALE
 * was used in @FT_Load_Glyph or @FT_Load_Char.
 *
 * The outline's tables are always owned by the object and are destroyed
 * with it.
 */
typedef struct FT_OutlineGlyphRec_ {
    FT_GlyphRec root;
    FT_Outline outline;
} FT_OutlineGlyphRec;


/* *************************************************************************
 *
 * @function:
 * FT_New_Glyph
 *
 * @description:
 * A function used to create a new empty glyph image.  Note that the
 * created @FT_Glyph object must be released with @FT_Done_Glyph.
 *
 * @input:
 * library ::
 * A handle to the FreeType library object.
 *
 * format ::
 * The format of the glyph's image.
 *
 * @output:
 * aglyph ::
 * A handle to the glyph object.
 *
 * @return:
 * FreeType error code.  0~means success.
 *
 * @since:
 * 2.10
 */
FT_EXPORT(FT_Error)
FT_New_Glyph(FT_Library library, FT_Glyph_Format format, FT_Glyph *aglyph);


/* *************************************************************************
 *
 * @function:
 * FT_Get_Glyph
 *
 * @description:
 * A function used to extract a glyph image from a slot.  Note that the
 * created @FT_Glyph object must be released with @FT_Done_Glyph.
 *
 * @input:
 * slot ::
 * A handle to the source glyph slot.
 *
 * @output:
 * aglyph ::
 * A handle to the glyph object.
 *
 * @return:
 * FreeType error code.  0~means success.
 *
 * @note:
 * Because `*aglyph->advance.x` and `*aglyph->advance.y` are 16.16
 * fixed-point numbers, `slot->advance.x` and `slot->advance.y` (which
 * are in 26.6 fixed-point format) must be in the range ]-32768;32768[.
 */
FT_EXPORT(FT_Error)
FT_Get_Glyph(FT_GlyphSlot slot, FT_Glyph *aglyph);


/* *************************************************************************
 *
 * @function:
 * FT_Glyph_Copy
 *
 * @description:
 * A function used to copy a glyph image.  Note that the created
 * @FT_Glyph object must be released with @FT_Done_Glyph.
 *
 * @input:
 * source ::
 * A handle to the source glyph object.
 *
 * @output:
 * target ::
 * A handle to the target glyph object.  0~in case of error.
 *
 * @return:
 * FreeType error code.  0~means success.
 */
FT_EXPORT(FT_Error)
FT_Glyph_Copy(FT_Glyph source, FT_Glyph *target);


/* *************************************************************************
 *
 * @function:
 * FT_Glyph_Transform
 *
 * @description:
 * Transform a glyph image if its format is scalable.
 *
 * @inout:
 * glyph ::
 * A handle to the target glyph object.
 *
 * @input:
 * matrix ::
 * A pointer to a 2x2 matrix to apply.
 *
 * delta ::
 * A pointer to a 2d vector to apply.  Coordinates are expressed in
 * 1/64th of a pixel.
 *
 * @return:
 * FreeType error code (if not 0, the glyph format is not scalable).
 *
 * @note:
 * The 2x2 transformation matrix is also applied to the glyph's advance
 * vector.
 */
FT_EXPORT(FT_Error)
FT_Glyph_Transform(FT_Glyph glyph, const FT_Matrix *matrix, const FT_Vector *delta);


/* *************************************************************************
 *
 * @enum:
 * FT_Glyph_BBox_Mode
 *
 * @description:
 * The mode how the values of @FT_Glyph_Get_CBox are returned.
 *
 * @values:
 * FT_GLYPH_BBOX_UNSCALED ::
 * Return unscaled font units.
 *
 * FT_GLYPH_BBOX_SUBPIXELS ::
 * Return unfitted 26.6 coordinates.
 *
 * FT_GLYPH_BBOX_GRIDFIT ::
 * Return grid-fitted 26.6 coordinates.
 *
 * FT_GLYPH_BBOX_TRUNCATE ::
 * Return coordinates in integer pixels.
 *
 * FT_GLYPH_BBOX_PIXELS ::
 * Return grid-fitted pixel coordinates.
 */
typedef enum FT_Glyph_BBox_Mode_ {
    FT_GLYPH_BBOX_UNSCALED = 0,
    FT_GLYPH_BBOX_SUBPIXELS = 0,
    FT_GLYPH_BBOX_GRIDFIT = 1,
    FT_GLYPH_BBOX_TRUNCATE = 2,
    FT_GLYPH_BBOX_PIXELS = 3

} FT_Glyph_BBox_Mode;


/* these constants are deprecated; use the corresponding */
/* `FT_Glyph_BBox_Mode` values instead                   */
#define ft_glyph_bbox_unscaled FT_GLYPH_BBOX_UNSCALED
#define ft_glyph_bbox_subpixels FT_GLYPH_BBOX_SUBPIXELS
#define ft_glyph_bbox_gridfit FT_GLYPH_BBOX_GRIDFIT
#define ft_glyph_bbox_truncate FT_GLYPH_BBOX_TRUNCATE
#define ft_glyph_bbox_pixels FT_GLYPH_BBOX_PIXELS


/* *************************************************************************
 *
 * @function:
 * FT_Glyph_Get_CBox
 *
 * @description:
 * Return a glyph's 'control box'.  The control box encloses all the
 * outline's points, including Bezier control points.  Though it
 * coincides with the exact bounding box for most glyphs, it can be
 * slightly larger in some situations (like when rotating an outline that
 * contains Bezier outside arcs).
 *
 * Computing the control box is very fast, while getting the bounding box
 * can take much more time as it needs to walk over all segments and arcs
 * in the outline.  To get the latter, you can use the 'ftbbox'
 * component, which is dedicated to this single task.
 *
 * @input:
 * glyph ::
 * A handle to the source glyph object.
 *
 * mode ::
 * The mode that indicates how to interpret the returned bounding box
 * values.
 *
 * @output:
 * acbox ::
 * The glyph coordinate bounding box.  Coordinates are expressed in
 * 1/64th of pixels if it is grid-fitted.
 *
 * @note:
 * Coordinates are relative to the glyph origin, using the y~upwards
 * convention.
 *
 * If the glyph has been loaded with @FT_LOAD_NO_SCALE, `bbox_mode` must
 * be set to @FT_GLYPH_BBOX_UNSCALED to get unscaled font units in 26.6
 * pixel format.  The value @FT_GLYPH_BBOX_SUBPIXELS is another name for
 * this constant.
 *
 * If the font is tricky and the glyph has been loaded with
 * @FT_LOAD_NO_SCALE, the resulting CBox is meaningless.  To get
 * reasonable values for the CBox it is necessary to load the glyph at a
 * large ppem value (so that the hinting instructions can properly shift
 * and scale the subglyphs), then extracting the CBox, which can be
 * eventually converted back to font units.
 *
 * Note that the maximum coordinates are exclusive, which means that one
 * can compute the width and height of the glyph image (be it in integer
 * or 26.6 pixels) as:
 *
 * ```
 * width  = bbox.xMax - bbox.xMin;
 * height = bbox.yMax - bbox.yMin;
 * ```
 *
 * Note also that for 26.6 coordinates, if `bbox_mode` is set to
 * @FT_GLYPH_BBOX_GRIDFIT, the coordinates will also be grid-fitted,
 * which corresponds to:
 *
 * ```
 * bbox.xMin = FLOOR(bbox.xMin);
 * bbox.yMin = FLOOR(bbox.yMin);
 * bbox.xMax = CEILING(bbox.xMax);
 * bbox.yMax = CEILING(bbox.yMax);
 * ```
 *
 * To get the bbox in pixel coordinates, set `bbox_mode` to
 * @FT_GLYPH_BBOX_TRUNCATE.
 *
 * To get the bbox in grid-fitted pixel coordinates, set `bbox_mode` to
 * @FT_GLYPH_BBOX_PIXELS.
 */
FT_EXPORT(void)
FT_Glyph_Get_CBox(FT_Glyph glyph, FT_UInt bbox_mode, FT_BBox *acbox);


/* *************************************************************************
 *
 * @function:
 * FT_Glyph_To_Bitmap
 *
 * @description:
 * Convert a given glyph object to a bitmap glyph object.
 *
 * @inout:
 * the_glyph ::
 * A pointer to a handle to the target glyph.
 *
 * @input:
 * render_mode ::
 * An enumeration that describes how the data is rendered.
 *
 * origin ::
 * A pointer to a vector used to translate the glyph image before
 * rendering.  Can be~0 (if no translation).  The origin is expressed
 * in 26.6 pixels.
 *
 * destroy ::
 * A boolean that indicates that the original glyph image should be
 * destroyed by this function.  It is never destroyed in case of error.
 *
 * @return:
 * FreeType error code.  0~means success.
 *
 * @note:
 * This function does nothing if the glyph format isn't scalable.
 *
 * The glyph image is translated with the `origin` vector before
 * rendering.
 *
 * The first parameter is a pointer to an @FT_Glyph handle, that will be
 * _replaced_ by this function (with newly allocated data).  Typically,
 * you would use (omitting error handling):
 *
 * ```
 * FT_Glyph        glyph;
 * FT_BitmapGlyph  glyph_bitmap;
 *
 *
 * // load glyph
 * error = FT_Load_Char( face, glyph_index, FT_LOAD_DEFAULT );
 *
 * // extract glyph image
 * error = FT_Get_Glyph( face->glyph, &glyph );
 *
 * // convert to a bitmap (default render mode + destroying old)
 * if ( glyph->format != FT_GLYPH_FORMAT_BITMAP )
 * {
 * error = FT_Glyph_To_Bitmap( &glyph, FT_RENDER_MODE_NORMAL,
 * 0, 1 );
 * if ( error ) // `glyph' unchanged
 * ...
 * }
 *
 * // access bitmap content by typecasting
 * glyph_bitmap = (FT_BitmapGlyph)glyph;
 *
 * // do funny stuff with it, like blitting/drawing
 * ...
 *
 * // discard glyph image (bitmap or not)
 * FT_Done_Glyph( glyph );
 * ```
 *
 * Here is another example, again without error handling:
 *
 * ```
 * FT_Glyph  glyphs[MAX_GLYPHS]
 *
 *
 * ...
 *
 * for ( idx = 0; i < MAX_GLYPHS; i++ )
 * error = FT_Load_Glyph( face, idx, FT_LOAD_DEFAULT ) ||
 * FT_Get_Glyph ( face->glyph, &glyphs[idx] );
 *
 * ...
 *
 * for ( idx = 0; i < MAX_GLYPHS; i++ )
 * {
 * FT_Glyph  bitmap = glyphs[idx];
 *
 *
 * ...
 *
 * // after this call, `bitmap' no longer points into
 * // the `glyphs' array (and the old value isn't destroyed)
 * FT_Glyph_To_Bitmap( &bitmap, FT_RENDER_MODE_MONO, 0, 0 );
 *
 * ...
 *
 * FT_Done_Glyph( bitmap );
 * }
 *
 * ...
 *
 * for ( idx = 0; i < MAX_GLYPHS; i++ )
 * FT_Done_Glyph( glyphs[idx] );
 * ```
 */
FT_EXPORT(FT_Error)
FT_Glyph_To_Bitmap(FT_Glyph *the_glyph, FT_Render_Mode render_mode, const FT_Vector *origin, FT_Bool destroy);


/* *************************************************************************
 *
 * @function:
 * FT_Done_Glyph
 *
 * @description:
 * Destroy a given glyph.
 *
 * @input:
 * glyph ::
 * A handle to the target glyph object.
 */
FT_EXPORT(void)
FT_Done_Glyph(FT_Glyph glyph);

/* */


/* other helpful functions */

/* *************************************************************************
 *
 * @section:
 * computations
 *
 */


/* *************************************************************************
 *
 * @function:
 * FT_Matrix_Multiply
 *
 * @description:
 * Perform the matrix operation `b = a*b`.
 *
 * @input:
 * a ::
 * A pointer to matrix `a`.
 *
 * @inout:
 * b ::
 * A pointer to matrix `b`.
 *
 * @note:
 * The result is undefined if either `a` or `b` is zero.
 *
 * Since the function uses wrap-around arithmetic, results become
 * meaningless if the arguments are very large.
 */
FT_EXPORT(void)
FT_Matrix_Multiply(const FT_Matrix *a, FT_Matrix *b);


/* *************************************************************************
 *
 * @function:
 * FT_Matrix_Invert
 *
 * @description:
 * Invert a 2x2 matrix.  Return an error if it can't be inverted.
 *
 * @inout:
 * matrix ::
 * A pointer to the target matrix.  Remains untouched in case of error.
 *
 * @return:
 * FreeType error code.  0~means success.
 */
FT_EXPORT(FT_Error)
FT_Matrix_Invert(FT_Matrix *matrix);

/* */


FT_END_HEADER

#endif /* FTGLYPH_H_ */


/* END */


/* Local Variables: */
/* coding: utf-8    */
/* End:             */
